In recent years, responding to a demand of reduction of expenses and time for business trips, television conference systems have spread as an example of a transmission system that conducts a television conference via a communication network, such as the Internet. In such a television conference system, the various type's of data, for example image data and audio data are transmitted/received between the television conference terminals as an example of transmission terminal to realize the television conference.
Furthermore, in the conventional television conference system, a relay device is used to relay the data transmitted from the television conference terminal to another television conference terminal. In this case, it is known that one relay device is selected from a plurality of candidate relay devices for each television conference in order to disperse a load of the relay device (see Patent Document 1 Japanese Patent Application Laid-Open Publication No. 2012-50063, which is incorporated herein by reference in its entirety). After the selection of a relay device is completed, a transmission management system that manages the television conference terminals controls to connect the television conference terminals with the selected relay device, so that a television conference can be commenced between the television conference terminals. In a case where a new television conference terminal participates in the television conference in execution, the transmission management system controls to connect the television conference terminal newly participating the television conference with a relay device being used in the television conference. Consequently, the television conference terminal newly participating in the television conference can perform transmission/reception of data to/from other television conference terminals that are conducting the television conference via the relay device, so that participating in the television conference is realized.
However, conventionally in a related transmission system, one transmission management system is used to control the start of communication. In a case where a lot of the starts of communication occur at the same time, the single transmission management system should control a plurality of connections between the transmission terminals and the relay devices. As a result, that leads significantly increase of the load applied to the one transmission management system. In a case where a plurality of transmission management systems is provided in order to disperse the loads, a transmission management system cannot recognize that which relay device is used to establish the communication when the communication is started through control by another transmission management system. As a result, when a new transmission terminal participates in the communication, the transmission management system cannot determine that which relay device should be connected to the newly participating transmission terminal. Therefore, the transmission management system cannot execute control associated with communication.